Upper and lower limb tremor in inflammatory neuropathies

Area of Science:

• Neurology
• Neuroscience
• Peripheral Nerve Disorders

Background:

• Neuropathic tremor mechanisms are not fully understood, with limited distinction between proximal and distal neuropathies.
• Lower limb tremor's role in imbalance is known in Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) but unexplored in other neuropathies.

Purpose of the Study:

• To characterize upper and lower limb tremor in Chronic Immune Sensory Polyradiculopathy (CISP) and Distal Acquired Demyelinating Neuropathy with anti-MAG antibodies (DADS-MAG).
• To contrast tremor characteristics in CISP and DADS-MAG with those in CIDP.

Main Methods:

• Cross-sectional study of 38 patients with CIDP, CISP, or DADS-MAG.
• Clinical assessment, tremor recording, nerve conduction studies, somatosensory evoked potentials, and force platform balance measurements were performed.

Main Results:

• Upper limb tremor was highly prevalent across all studied neuropathies (66-100%).
• Lower limb tremor was present in 29-66% of patients and correlated with imbalance.
• Nerve conduction parameters linked to upper limb tremor in DADS-MAG/CISP and imbalance in CISP.

Conclusions:

• Upper limb tremor involves peripheral and central mechanisms, irrespective of neuropathy type (distal/proximal).
• Lower limb tremor is associated with peripheral nerve function and contributes to patient imbalance.